Accounting for upstream culvert capacity in the peak flow at downstream culverts

[gassc]

Currently upstream culvert capacity is not accounted for in the calculation of peak flow at downstream culverts. This is because we run a delineation for every culvert individually.

To account for the modulation of incoming flow by upstream culverts, we'd need:

• to delineate a watersheds in the AOI at once and get a layer of non-overlapping boundaries
• determine the network relationship between a culvert and any upstream or downstream culverts

In the original https://github.com/civicmapper/peak-flow-calculator/ toolbox, we ran watershed delineation on all locations at once, with the results being non-overlapping watersheds.

Creating a network may just be a matter of having those watershed boundaries (as a grid), a flow accumulation grid, and some TBD map algebra.